MRSA Heart Infection (Endocarditis)

Overview

Endocarditis is an infection of the lining of the heart, usually involving the heart valves, whereby bacteria have direct communication with the bloodstream. Endocarditis is concerning because of the potential for:

• Heart valve damage and/or
• Bloodstream infections  

Examination

• High fevers are common.
• Patients usually appear quite ill.
• Heart murmurs may be present – either preexisting or new onset secondary to heart valve damage.
• Other symptoms may include weakness, body aches and fatigue.

Diagnosis

The diagnosis of endocarditis is often challenging. The history and physical may provide clues to the diagnosis; however, diagnostic testing is necessary for a definitive diagnosis. Tests include: echocardiogram (ultrasound of the heart), and blood cultures.

• History and physical findings that prompt further testing:
  • The patient had a procedure that can introduce bacteria into the bloodstream. Procedures may include dental work, IV drug use, among others.
  • The patient has a preexisting heart murmur. Blood flows through the heart via a circuit of four valves. Heart murmurs may indicate a misshaped, narrowed, or leaky valve. Abnormal valves can give rise to turbulent blood flow, heard as a murmur. The abnormal flow or churning of blood allows circulating bacteria time to attach, and infect a heart valve.    
  • The patient develops a new heart murmur, which may imply an infected heart valve.
• An echocardiogram is used to diagnose heart valve infections.  
  • An echocardiogram is an ultrasound of the heart that is able to visualize heart valves and blood flow.
  • Infections are seen as clusters of bacteria on the heart valves, called vegetations.
  • The ultrasound may be obtained by looking through the chest wall; however, the ribs and chest tissue can obscure the heart.
  • A trans-esophageal echocardiogram (TEE) is the test of choice to best view vegetations on the heart valves. The ultrasound probe is fed into the esophagus (food tube), which lies in close proximity to the heart. The TEE provides an unobstructed, better view of the heart and heart valves.  
• Blood cultures are often helpful. In endocarditis, bacteria are in direct communication with the bloodstream; therefore, bloodstream infections are common. A sample of blood is sent to the lab fortesting. Success enables you to know the exact bacteria causing the infection, and which antibiotics will best treat the infection.